Two children are pulling on opposite sides of a blanket. The brother is pulling with a force of 3 N. The sister is pulling with
1 answer:
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Answer:
The initial velocity is 0.5114 m/s or 511.4 mm/s
Explanation:
Let the initial velocity be 'v'.
Given:
Mass of the ball (m) = 130 g = 0.130 kg [ 1 g = 0.001 kg]
Initial height of the ball (h₁) = 1.4 mm = 0.0014 m [ 1 mm = 0.001 m]
Final height of the ball (h₂) = 15 mm = 0.015 m
Now, from conservation of energy principle, energy can neither be created nor be destroyed but converted from one form to another.
Here, the kinetic energy of the ball is converted to gravitational potential energy of the ball after reaching the final height.
Change in kinetic energy is given as:
As it just touches the 15 mm high roof, the final velocity will be zero. So,
.
Now, the change in kinetic energy is equal to:
Change in gravitational potential energy = Final PE - Initial PE
So,
[ g = 9.8 m/s²]
Now, Change in KE = Change in PE
Therefore, the initial velocity is 0.5114 m/s or 511.4 mm/s
Answer: The drag force goes up by a factor of 4
Explanation:
The <u>Drag Force</u> equation is:
(1)
Where:
is the Drag Force
is the Drag coefficient, which depends on the material
is the density of the fluid where the bicycle is moving (<u>air in this case)
</u>
is the transversal area of the body or object
the bicycle's velocity
Now, if we assume ,
and
do not change, we can rewrite (1) as:
(2)
Where groups all these coefficients.
So, if we have a new velocity , which is the double of the former velocity:
(3)
Equation (2) is written as:
(4)
Comparing (2) and (4) we can conclude<u> the Drag force is four times greater when the speed is doubled.</u>